6.11
Date Code 20171006 Instruction Manual SEL-400 Series Relays
Autoreclosing
Two-Circuit-Breaker Autoreclosing
recloser proceeds to timing SPOID (Single-Pole Open Interval Delay). The
recloser goes to lockout if the circuit breakers fail to open (no close attempts fol-
low). If an evolving fault results in a three-pole trip condition that asserts 3PARC,
then the recloser exits the 79CY1 cycle and goes to the three-pole cycle 79CY3.
When E79 := Y1, a Single-Pole Open Interval Supervision Condition (SPOISC)
must be satisfied before the recloser can proceed to timing SPOID. If the supervi-
sory condition is not met within the duration of timer SPOISD (Single-Pole Open
Interval Supervision Delay), the recloser goes to lockout.
After single-pole open interval time SPOID expires, the recloser closes the leader
if the single-pole open condition is still in effect and supervisory condition
SPnCLS (Single-Pole BKn Reclose Supervision) is satisfied within the duration
of timer BKnCLSD (BKn Reclose Supervision Delay). If the leader circuit
breaker has more than one pole open at the end of the SPOID time, the recloser
sends the leader to lockout BKnLO.
At the leader close command, the recloser starts timer BKCFD (Breaker Close
Failure Delay). If the leader fails to close, the recloser sends the leader to lockout
after timer BKCFD expires. If the leader closes within the BKCFD time, the
recloser goes to SPRCD (Single-Pole Reclaim Time Delay) reclaim timing if
NBK1 is asserted, or prepares to close the follower circuit breaker if NBK2 is
asserted.
To close the follower circuit breaker, the recloser checks for two active circuit
breakers in the scheme. If NBK2 is asserted, the recloser checks for a single-pole
open on the follower and starts timer TBBKD (Time Between Breakers For
ARC). If multiple poles of the follower circuit breaker are open, the recloser
sends the follower to lockout BKnLO. When TBBKD expires, the recloser closes
the follower breaker if FBKCEN (Follower Breaker Closing Enable) is asserted
and supervisory condition SPnCLS is satisfied within the duration of timer
BKnCLSD. At the follower close command, the recloser starts timer BKCFD
(Breaker Close Failure Delay). If the follower fails to close, the recloser sends the
follower to lockout after timer BKCFD expires. If the leader circuit breaker is not
in lockout, the recloser begins timing SPRCD reclaim time for the leader.
If the follower breaker closes successfully, the recloser starts the SPRCD (Single-
Pole Reclaim Time Delay) timer if 79BRCT (Block Reclaim Timer) is not asserted.
SPRCD Reclaim Timing
The recloser determines subsequent state transitions during reclaim timing
according to the status of Relay Word bit SPLSHT (Single-Pole Reclose Last
Shot). When SPLSHT is asserted, the recloser forces all subsequent relay trips to
three-pole only mode.
SPLSHT Deasserted (Single-Pole Shot Remains)
The recloser exhibits four possible state transitions when SPLSHT is not asserted:
➤ If no further trip conditions occur and timer SPRCD expires, the
recloser returns to the reset states BKnRS.
➤ If a single-phase fault occurs while the SPRCD reclaim timer is
timing, then the recloser asserts SPARC if all single-pole initiate
conditions are satisfied and goes to the beginning of the 79CY1
cycle. The recloser then recalculates and freezes the calculation for
the number of active circuit breakers, the leader, and the follower.
The recloser then increments the shot counter and begins the next
open interval timer.
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